U.S. patent application number 12/437798 was filed with the patent office on 2010-11-11 for apparatus and method for retaining a document during imaging.
This patent application is currently assigned to HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P.. Invention is credited to Edward A. Hill, Ken Ko.
Application Number | 20100284044 12/437798 |
Document ID | / |
Family ID | 43062194 |
Filed Date | 2010-11-11 |
United States Patent
Application |
20100284044 |
Kind Code |
A1 |
Ko; Ken ; et al. |
November 11, 2010 |
Apparatus and Method for Retaining a Document During Imaging
Abstract
Disclosed are apparatuses and methods for holding a document
sheet in place against a scanning surface of an image capture
system. One such apparatus is a document cover comprising: a body
that is oriented parallel to the scanning surface when the document
cover is in the closed position; a compliant and elastic document
backing that is partially attached to the body and configured to
reflect light originating from the image capture system; and a
backing constraint configured to secure a central region of the
document backing to the body and further configured to constrain
movement of the central region in a first direction that is normal
to the scanning surface while allowing movement in the same
direction of outer regions that are lateral to the central region.
The document backing generates a downward spring force which biases
the outer regions toward the platen.
Inventors: |
Ko; Ken; (San Diego, CA)
; Hill; Edward A.; (Oceanside, CA) |
Correspondence
Address: |
HEWLETT-PACKARD COMPANY;Intellectual Property Administration
3404 E. Harmony Road, Mail Stop 35
FORT COLLINS
CO
80528
US
|
Assignee: |
HEWLETT-PACKARD DEVELOPMENT
COMPANY, L.P.
Houston
TX
|
Family ID: |
43062194 |
Appl. No.: |
12/437798 |
Filed: |
May 8, 2009 |
Current U.S.
Class: |
358/474 |
Current CPC
Class: |
G03G 2215/00185
20130101; G03G 15/605 20130101; H04N 2201/0422 20130101; H04N 1/10
20130101 |
Class at
Publication: |
358/474 |
International
Class: |
H04N 1/04 20060101
H04N001/04 |
Claims
1. A document cover for retaining a document sheet against a
scanning surface of an image capture system, the document cover
comprising: a body that is oriented substantially parallel to the
scanning surface when the document cover is in the closed position;
a compliant and elastic document backing that is partially attached
to the body and configured to reflect light originating from the
image capture system; and a backing constraint configured to secure
a central region of the document backing to the body and further
configured to constrain movement of the central region in a first
direction that is normal to the body in the closed position while
allowing movement, in the first direction, of outer regions that
are lateral to the central region, the document backing generating
a downward spring force which biases the outer regions toward the
scanning surface when the document cover is in the closed
position.
2. The document cover of claim 1, wherein the document backing
comprises a sheet of synthetic paper.
3. The document cover of claim 1, wherein the backing constraint
comprises adhesive applied between the central region of one
surface of the document backing, and a corresponding central region
on an opposing surface of the body.
4. The document cover of claim 1, wherein the backing constraint is
further configured to limit movement of the document backing in a
second direction that is parallel to the scanning surface.
5. The document cover of claim 1, the body being attached to the
image capture system by a hinge assembly.
6. An image capture system for scanning a document sheet, the
system comprising: a platen configured to support the document
sheet; an image capture unit configured to scan an image of the
document sheet arranged on the platen; a document cover configured
to retain the document sheet in place against the platen, the
document cover comprising: a hinge assembly configured to attach
the document cover to a bed of the image capture system, and
further configured to pivot the cover between an open and a closed
position; a body that is oriented parallel to the platen when the
document cover is in the closed position; a compliant and elastic
document backing that is partially attached to the body and
configured to reflect light originating from the image capture unit
back to the image capture unit; and a backing constraint configured
to secure a central region of the document backing to the body and
further configured to constrain movement of the central region in a
first direction that is normal to the body in the closed position,
the backing constraint further configured to allow movement, in the
first direction, of outer regions that are lateral to the central
region, the document backing in combination with the backing
constraint generating a downward spring force which biases the
outer regions toward the platen.
7. The image capture system of claim 6, wherein the document
backing comprises a sheet of synthetic paper.
8. The image capture system of claim 6, wherein the backing
constraint comprises an adhesive layer applied between the central
region of one surface of the document backing, and a corresponding
central region on an opposing surface of the body.
9. The image capture system of claim 6, wherein the backing
constraint is further configured to limit movement of the document
backing in a second direction that is parallel to the scanning
surface.
10. A method of assembling a document cover for holding a document
sheet in place against a scanning surface of an image capture
system, the document cover including a body and a document backing,
the method comprising: providing the body, the body being oriented
parallel to the scanning surface when the document cover is in a
closed position; providing the document backing, the backing being
compliant and elastic and having at least one surface configured to
reflect light originating from the image capture unit; and adhering
a central region of the document backing to the body while leaving
outer regions that are lateral to the central region free of
adhesive, such that movement of the central region is constrained
in a direction that is normal to the scanning surface while
movement of the outer regions in the same direction is allowed,
thereby generating a spring force which biases the outer regions
toward the scanning surface when the document cover is in a closed
position; and hingedly attaching the document cover to the image
capture system.
11. The method of claim 10, wherein the document backing comprises
a sheet of synthetic paper.
12. The method of claim 10, wherein the adhering comprises applying
an adhesive between the central region of one surface of the
document backing, and a corresponding central region on an opposing
surface of the body.
13. The method of claim 10, wherein adhering is such that movement
of the document backing is limited in a second direction that is
parallel to the scanning surface.
Description
BACKGROUND
[0001] In some document imaging systems, the imaging sensor or
capture unit must locate the document on the scanning surface in
order to focus properly. If the document cannot be located
properly, image quality will degrade. For example, a document that
is not flat against the scanning surface because of wrinkles or
folds in the document results in blurry text and out-of-focus
graphics. Some of these imaging systems use a white background that
is placed behind the document to locate the document's vertical
position relative to the scanning surface. Even so, conventional
imaging systems typically produce images with reduced quality when
the document does not rest flat against the scanning surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] Many aspects of the disclosure can be better understood with
reference to the following drawings. The components in the drawings
are not necessarily to scale, emphasis instead being placed upon
clearly illustrating the principles of the present disclosure.
[0003] FIG. 1 is a sectional view of one embodiment of an image
capture system, in a closed state.
[0004] FIG. 2 is a bottom view of the lid from FIG. 1 in one
embodiment of an image capture system.
[0005] FIG. 3 is a sectional side view of one embodiment of an
image capture system from FIG. 1, in an open or document receiving
position.
[0006] FIG. 4 is a close-up of the sectional side view of FIG.
3.
[0007] FIG. 5 is a sectional side view of one embodiment of an
image capture system from FIG. 1, in an closed or document imaging
position.
[0008] FIG. 6 is a close-up of the sectional side view of FIG.
5.
DETAILED DESCRIPTION
[0009] The techniques disclosed herein allow a document sheet to be
kept in close proximity to a image capture unit during a scanning
process. A document backing piece of the unit's lid urges outer
regions of the document sheet closer to the flat scanning surface,
thus improving the image quality. Various embodiments are now
discussed with reference to the figures.
[0010] FIG. 1 is a sectional view of image capture system 100 in a
closed state. Image capture system 100 is configured to scan or
capture an electronic image from a sheet 110, and includes a bed
120 and a lid 130. (Lid 130 is also referred to herein as a
document cover.) Bed 120 comprises includes platen 140 and image
capture unit 150. Platen 140 is configured to support sheet 110.
Platen 140 serves as the scanning surface and acts as a window
through which an image of sheet 110 is captured. Platen 140
includes a transparent panel or plate which may be made of glass,
plastic, or other suitable materials known to a person of ordinary
skill in the art. Image capture unit 150 includes electrical and/or
optical components configured to acquire, capture, sense, or scan
images from sheet 110, through platen 140. In some embodiments,
image capture unit 150 is moved across or along platen 140. In
other embodiments, image capture unit 150 remains stationary and is
configured to concurrently capture information from substantially
an entire surface area of platen 140.
[0011] Lid 130 is configured to retain sheet 110 in place against
platen 140 during a scan by image capture unit 150. Lid 130
includes body 160, which is pivotally attached to bed 120 by hinge
assembly 170, such that lid 130 may be pivoted between an open, or
document receiving, state and a closed, or scanning, state. When
lid 130 is in the closed state, body 160 is configured to rest upon
platen 140 (and is thus oriented parallel to platen 140), thereby
inhibiting environmental light from passing through platen 140.
Although this example embodiment uses a hinge assembly, other
embodiments use mechanisms other than a hinge to movably support
lid 130 relative to bed 120.
[0012] Lid 130 also includes document backing 180. Document backing
180 includes a substantially planar panel, that is sized and shaped
so as to overlay platen 140 when lid 130 is in the closed state (as
in FIG. 1). Document backing 180 is configured to reflect light
originating from image capture unit 150 back to a sensing device or
element associated with image capture unit 150. In this regard, in
one embodiment the lower surface of document backing 180 is white,
though in other embodiments the lower surface may be colored. In
some embodiments, document backing 180 has dimensions corresponding
to a standard paper size (e.g., 8.5''.times.11'', 8.5''.times.14'',
210 mm.times.297 mm, etc.). However, the principles described
herein also apply to a document backing 180 with nonstandard
dimensions.
[0013] FIG. 2 is a bottom view of lid 130. A backing constraint 210
secures or attaches a portion of document backing 180 to body 160
of lid 130, thus supporting document backing 180 relative to body
160. More specifically, backing constraint 210 attaches so as to
limit or constrain the extent to which a central region 220 of
document backing 180 may move in the direction (310 in FIG. 3) that
is normal to the plane of document backing 180 while also allowing
outer regions 230a, 230b of document backing 180 to move in
direction 310. When lid 130 is in the closed position, direction
310 is also normal to platen 140 so that direction 310 is
toward/away from platen 140. In typical usage, direction 310 is
generally vertical. Backing constraint 210 also limits the extent
to which document backing 180 may move in the plane (240) of
document backing 180.
[0014] In some embodiments, backing constraint 210 takes the form
of adhesive applied between one surface of document backing 180 and
an opposing surface of lid 130, generally within central region 220
of document backing 180 and within a corresponding region of the
opposing lid surface. In one embodiment, backing constraint 210 is
an acrylic layer with adhesive on both sides and that is
pressure-sensitive. In some embodiments, the adhesive glues
document backing 180 directly to lid 130, with no intermediate
layers. In some embodiments, the adhesive is generally continuous
throughout central region 220. In other embodiment, the adhesive is
not continuous within central region 220, but is instead applied
intermittently, for example, in stripes or dots, or in a zigzag
fashion.
[0015] Lid 130 and document backing 180 work as follows to improve
image quality during a scan. FIG. 3 illustrates a sectional side
view of image capture system 100 in an open or document receiving
position. Sheet 110 is placed on platen 140 while lid 130 is an
open position. In this open position, with no structure pressing
down upon sheet 110, those portions of sheet 110 which are slightly
irregular (e.g., folds and wrinkles) are not in close contact with
platen 140. (See the close-up sectional side view of FIG. 4.) This
can reduce image quality of a scan, for example, blurring of
scanned text or an out-of-focus picture. Document backing 180 is
made of a compliant and elastic material, which in combination with
backing constraint 210 (and in particular with the location of
constraint 210), leaves outer regions 230A,230B of constraint 210
free to sag toward platen 140 under gravitational forces. This sag
is also seen in the close-up sectional side view of FIG. 4. In some
embodiments, document backing 180 is a sheet of synthetic paper. As
should be understood by a person of ordinary skill in the art, one
embodiment of synthetic paper is a thin polypropylene plastic film.
In some embodiments, document backing 180 is a thin sheet, with a
thickness on the order 0.20-0.30 mm.
[0016] FIG. 5 illustrates a sectional side view of image capture
system 100 in an closed or document imaging position. The downward
sag of outer regions 230A,230B of backing constraint 210, combined
with the elastic property of document backing 180, gives document
backing 180 a compliant characteristic which generates a downward
spring force. This spring force in turn biases or flattens sheet
110, and since outer regions 230A, 230B are unconstrained, these
regions are urged toward platen 140. In this manner, irregularities
in the regions of sheet 110 that correspond to outer regions
230A,230B of document backing 180 are urged toward image capture
unit 150, resulting in improved image quality. This sag is also
seen in the close-up sectional side view of FIG. 6.
[0017] In operation, lid 130 is positioned in the open stage shown
in FIG. 3, and a sheet 110 is arranged on platen 140. As lid 130 is
closed document backing 180 generates a downward spring force
against sheet 110. In the fully closed position (see FIG. 5)
document backing 180 continues to apply a force which flattens
sheet 110 and ensures that sheet 110 is snug against platen
140.
[0018] The foregoing description, for purposes of explanation, has
been described with reference to specific embodiments. However, the
illustrative discussions above are not intended to be exhaustive or
to limit the invention to the precise forms disclosed. Many
modifications and variations are possible in view of the above
teachings. The embodiments were chosen and describe in order to
best explain the principles of the invention and its practical
applications, to thereby enable others skilled in the art to best
utilize the invention and various embodiments with various
modifications as are suited to the particular use contemplated.
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